水土溶液润滑下犁铧表面仿生微织构的减摩抗磨特性研究

Anti-friction and Wear-resistance Characteristics of Biomimetic Microtextures on Plowshare Surfaces under Soil-water Mixture Lubrication

目的改善犁铧在犁耕作业中的减摩抗磨性能。方法以65Mn钢作为犁铧材料基体,采用激光加工技术在65Mn钢表面制备仿蚯蚓头部凹坑与仿蜣螂头部凹槽织构,在水土溶液中开展摩擦学性能试验,采用扫描电镜分析摩擦磨损机制,使用Ansys Fluent数值模拟辅助分析织构犁铧表面的润滑机理,然后利用Navier-Stokes公式分析犁铧织构表面流速和压力分布。结果犁用65Mn钢表面仿蜣螂头部凹坑与仿蚯蚓头部凹槽织构率为20%时具有最优的减摩抗磨性能,与未织构试样相比,摩擦因数分别降低了21.8%和47.3%,磨损率分别降低了18.0%和28.8%。Ansys Fluent数值模拟表明,2类仿生织构试样表面的流体动力润滑能生成一个净正压力区域,增厚润滑油膜,更易产生气穴与空化,降低压力,减少接触面的摩擦,从而有效增强了试样表面的减摩抗磨性能。结论在65Mn钢表面设计不同织构率的仿蜣螂头部凹坑与仿蚯蚓头部凹槽织构可以有效提高犁铧表面的减摩抗磨效果,且在水土溶液润滑下织构率为20%时,凹槽织构能获得最佳的动力润滑和减摩抗磨性能。

Plowshares play a pivotal role in agricultural operations,coming into direct contact with moist sand,soil,and gravel while enduring substantial impact loads.This constant interaction can lead to frictional wear and damage,resulting in reduced efficiency and increased agricultural expenses.To address these issues and improve the anti-friction and wear-resistance of plowshares,ultimately extending their lifespan and reducing the costs associated with farming,the work aims to explore an innovative approach involving the use of surface texturing.In this research,65 Mn steel was chosen as the fundamental material for the plowshares.To enhance their performance,laser processing technology was employed to create biomimetic textures on the steel surface.These textures emulated the depressions found on the heads of earthworms and dung beetles,and they were meticulously designed to have a uniform size of 300μm.Simulated plowing tests were conducted with an HSR-2M reciprocating friction and wear testing machine under simulated agricultural conditions of a 200-meter sliding distance,a 50 N loading force,and lubrication involving a mixture of soil and solutes.To gain deeper insights into the surface microstructure and the nature of frictional wear,scanning electron microscopy(SEM)was employed for detailed observations.Furthermore,Ansys Fluent numerical simulations were conducted to provide a comprehensive understanding of the lubrication mechanism on the textured plowshare surface.Fluid models were developed with parameters such as the Mach number and Reynolds number,and the Navier-Stokes equations were utilized to analyze the flow velocity and pressure distribution on the textured surface.The research findings were indeed remarkable.Plowshares made from 65Mn steel with a 20%texture rate,emulating the depressions on the heads of dung beetles and earthworms,exhibited the best anti-friction and wear-resistance properties.In comparison to non-textured samples,these textured plowshares demonstrated a substantial reduction in friction coefficients by 21.8%and 47.3%,and wear rates were lowered by 18.0%and 28.8%,respectively.The results from the Ansys Fluent numerical simulations provided further insights.Both types of biomimetic textures on the plowshare surface allowed for fluid dynamic lubrication,resulting in the generation of a net positive pressure region.This phenomenon increased the thickness of the lubricating oil film,making it easier to form cavities and aeration.The outcome was a reduction in pressure and diminished friction on the contact surfaces,effectively enhancing the anti-friction and anti-wear properties of the plowshare.In summary,plowshares constructed from 65 Mn steel,featuring a 20%texture rate and imitating the depressions on the heads of dung beetles and earthworms,deliver optimal anti-friction and anti-wear properties.These textured surfaces,particularly when being subject to dynamic lubrication in a mixture of soil and solutes,exhibit enhanced anti-friction and anti-wear capabilities.Furthermore,groove textures are proved to be superior to dent textures,boasting a larger capacity for storing lubricant and debris.This characteristic allows them to create a more robust dynamic pressure lubrication effect,further reducing friction and wear.This groundbreaking approach holds great promise for significantly extending the lifespan of plowshares while decreasing the overall costs associated with agricultural practices.